This invention relates to an image input/output apparatus, image input/output processing method and cartridge and, more particularly to an image input/output apparatus and an image input/output processing method for reading an original image and for printing an image on a print sheet and to a cartridge used for reading the original image.
Conventionally, a printer having a printhead for printing according to an ink-jet method or thermal transfer method, attached to a carriage, is used as an output device for a personal computer, a word processor and the like. The printer prints an image on a print sheet by scanning the carriage.
Further, a printer is known that can operate as a scanner. The printer reads an original image by using an image reading unit such as a COD having a photoelectric conversion function. The image reading unit is mounted on the carriage in place of the printhead. The printer inputs the read image data into a personal computer, a word processor or the like.
However, in the above conventional printer, the image printing width and the printing resolution of the printhead are somewhat different from the image reading width and the reading resolution of the image reading unit. In this case, as the printing period of the image printing operation is different from the image reading period of the image reading operation, the moving speed of the carriage to move the printhead and that to move the image reading unit are different. This complicates controls of carriage motors, and increases the memory capacity for storing information necessary for these controls, thus increasing the production cost of the apparatus.
Accordingly, it is an object of the present invention to provide an image input/output apparatus and image input/output processing method which enable image printing and image reading with simple control.
It is another object of the present invention to provide a cartridge used for reading an original with easy control.
According to one aspect of the present invention, the foregoing object is attained by providing an image input/output apparatus capable of performing an image output or original image reading by attaching to a carriage either an exchangeable printhead for printing an image on a print medium or exchangeable image reading head for reading an original image. The apparatus includes a scanning unit which scans the carriage; print period generation means for generating a print period control signal corresponding to a period of driving the printhead; and reading period generation means for generating a reading period control signal corresponding to a period of a reading operation by the image reading head, based on the printing period control signal. When reading the original image by attaching the image reading head to the carriage, the reading operation is performed based on the reading period control signal generated by the reading period generation means.
It is preferable that the printhead includes a plurality of print elements, the image reading head includes a plurality of reading elements, and a printing width corresponding to the plurality of print elements of the printhead and a reading width corresponding to the plurality of reading elements of the image reading head are the same.
In this case, it is more preferable that:
a printing resolution by the plurality of print elements of the printhead and a reading resolution by the plurality of reading elements of the image reading head are the same,
a spatial interval of the plurality of print elements of the printhead and a spatial interval of the plurality of reading elements of the image reading head are the same, or
the number of the plurality of printing elements of the printhead and the number of the plurality of reading elements of the image reading head are the same.
It is also preferable that a period of the printing period control signal and that of the reading period control signal are the same.
It is also preferable that the reading period generation means generates the reading period control signal as a signal obtained by multiplying a period of the printing period control signal by an integer. By doing this, it is possible that a reading resolution of the image reading head in the reading operation is reduced to a printing resolution of the printhead part of an integer, using the reading period control signal generated by the reading period generation means.
Further, as another preferred embodiment, if the reading period control signal is a clock pulse signal having a predetermined frequency, it is possible that the reading period generation means generates another clock pulse signal whose frequency is the predetermined frequency part of an integer, and a reading resolution of the image reading head in the reading operation is reduced to a printing resolution of the printhead part of the integer, using the reading period control signal generated by the reading period generation means.
Furthermore, as still another preferred embodiment, it is preferable that the reading period generation means generates the reading period control signal as a signal having a period obtained by dividing a period of the printing period control signal by an integer. By doing this, it is possible that a reading resolution of the image reading head in the reading operation is increased to the integral multiple of a printing resolution of said printhead, by using the reading period control signal generated by the read period generation means.
On the other hand, if the printing period control signal is a clock pulse signal having a predetermined frequency, it is possible that the reading period generation means generates another clock pulse signal whose frequency is an integral multiple of the predetermined frequency, and a reading resolution of the image reading head in the reading operation is increased to the integral multiple of a printing resolution of the printhead, by using the reading period control signal generated by the reading period generation means.
It is preferable that the image reading head includes: a light-emitting device, such as an LED, emitting light on the original; and a photo-reception device, such as a photoelectric transducer which generates an electric signal in accordance with received light intensity, receiving the light which has been emitted by the light-emitting device and reflected by the original.
As described above, in a case where the printhead includes a plurality of print elements, and the image reading head includes a plurality of reading elements, it may be arranged that a printing resolution by the plurality of print elements of the printhead and a reading resolution by the plurality of reading elements of the image reading head are different from each other, and the printing resolution is neither an integral multiple of the reading resolution nor the reading resolution part of an integer.
In this case, it is more preferable that:
a spatial interval of the plurality of print elements of the printhead and a spatial interval of the plurality of reading elements of the image reading head are different from each other, or
a period of the printing period control signal is neither an integral multiple of a period of the reading period control signal nor a value obtained by dividing the period of the reading period control signal by an integer.
By doing this, if the printing period control signal is a clock pulse signal having a predetermined frequency, and it is possible that the reading period generation means generates another clock pulse signal whose frequency is neither the integral multiple of the predetermined frequency nor the predetermined frequency part of the integer.
Furthermore, it is preferable that the apparatus further comprises regulation means for synchronizing a signal pulse of the reading period control signal generated by the reading period generation means with a signal pulse of the printing period control signal at predetermined intervals. In this case, it is preferable that the predetermined interval is determined based on the period of the reading period control signal generated by the reading period generation means and the period of the printing period control signal.
It is desirable that the above apparatus further includes a feeding unit which feeds the print medium or the original.
It should be noted that the above-described printhead is an ink-jet printhead that performs printing by discharging ink, and the ink-jet printhead preferably has electrothermal transducers to generate thermal energy to be supplied to ink so as to discharge the ink by utilizing the thermal energy.
According to another aspect of the present invention, the foregoing object is attained by providing an image input/output processing method operative in an image input/output apparatus capable of performing an image output or original image reading by attaching to a carriage either an exchangeable printhead for printing an image on a print medium or an exchangeable image reading head for reading an original image and scanning the carriage. The method includes a print period generation step of generating a print period control signal corresponding to a period of driving the printhead; and a reading period generation step of generating a reading period control signal corresponding to a period of a reading operation by the image reading head, based on the printing period control signal, wherein when reading the original image with the image reading head being attached to the carriage, the reading operation is performed based on the reading period control signal generated in the reading period generation step.
It is preferable that a period of the generated reading period control signal is the same as that of the printing period control signal, an integral multiple of that of the printing period control signal or a value obtained by dividing that of the printing period control signal by an integer.
Alternatively, if the method further includes a regulation step of synchronizing a signal pulse of the reading period control signal with a signal pulse of the printing period control signal at predetermined intervals, it is preferable that a period of the generated reading period control signal is not the same as that of the printing period control signal, an integral multiple of that of the printing period control signal or a value obtained by dividing that of the printing period control signal by an integer.
According to still another aspect of the present invention, the foregoing object is attained by providing a cartridge usable in an image input/output apparatus that performs image printing and image reading by attaching one of a plurality of exchangeable cartridge to a carriage and scanning the carriage. The cartridge includes a plurality of elements arranged in a predetermined resolution; and generation means for generating a driving period control signal indicating a period of driving the plurality of elements, based on a signal, indicating a predetermined period, generated by the apparatus.
Note that the plurality of elements are preferably reading elements for reading an original. If the cartridge further comprises a light-emitting device, S such as an LED, emitting light on the original, the plurality of elements can be photo-reception devices, such as photoelectric transducers that generate an electric signal in accordance with received light intensity, receiving the light emitted from the light-emitting device and reflected by the original.
It is preferable that the signal indicating the predetermined period is applicable to another cartridge attachable to the carriage.
It is also noted that:
the signal indicating the predetermined period is capable of being supplied via the carriage;
in a case where the plurality of elements are reading elements for reading an original, the cartridge functions as a reading cartridge for reading the original;
in a case where the plurality of elements are printing elements for printing on a print medium, the cartridge functions as a printhead, and
the signal indicating the predetermined period is used for driving the printhead.
It is preferable that a period of the driving period control signal generated by the generation means is the same as the predetermined period, an integral multiple of the predetermined period or the predetermined period part of an integer.
On the other hand, if the cartridge further comprises regulation means for synchronizing the signal indicating the predetermined period with the driving period control signal at predetermined intervals, it is also preferable that a period of the driving period control signal is not the same as the predetermined period, an integral multiple of the predetermined period or the predetermined period part of an integer.
In accordance with the present invention as described above, upon performing an image output or original image reading by attaching to a carriage either an exchangeable printhead for printing an image on a print medium or exchangeable image reading head for reading an original image and scanning the carriage, a print period control signal corresponding to a period of driving the printhead is generated, while a reading period control signal corresponding to a period of a reading operation by the image reading head is generated based on the printing period control signal, and the reading operation is performed based on the generated reading period control signal when reading an original image with the image reading head being attached to the carriage.
The present invention is particularly advantageous since it make separate control circuits respectively for the printing operation and the reading operation unnecessary by providing a common control circuit. This simplifies the apparatus construction, and reduces the cost of the apparatus.
Also, it is advantageous since an operation of reading an original is performed with simple control.
Further, for example, the reading period control signal is generated by multiplying the period of the printing period control signal by an integer, and the reading resolution of the image reading head is reduced to the printing resolution part of an integer by using the generated reading period control signal. Thus, since the photo-reception amount at the photoelectric transducer of the image reading head can be an integral multiple of that when the reading resolution and the printing resolution are the same, in reading a multivalued image, a sufficient light amount for discriminating the tone level can be obtained.
Furthermore, even though there is a case where the reading period control signal corresponding to the reading resolution is neither an integral multiple of the printing period control signal corresponding to the printing resolution nor that part of an integer, for example, the printing resolution is 360 dpi (dots/inch) while the reading resolution is 300 dpi, an appropriate reading period control signal can be generated based on the printing period control signal by adding a simple circuit. Thus, a resolution required by an application software program for image processing or character recognition can be easily obtained.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same name or similar parts throughout the figures thereof.